diff --git a/ctwrap/output.py b/ctwrap/output.py
index 459ccdf..e310d3d 100644
--- a/ctwrap/output.py
+++ b/ctwrap/output.py
@@ -236,7 +236,7 @@ def save(self, data, entry, variation=None, mode=None, errored=False):
                 df = pd.read_csv(fname)
             else:
                 df = pd.DataFrame(columns=row.keys())
-            df = df.append(row, ignore_index=True)
+            df = pd.concat([df, row], ignore_index=True)
             df.to_csv(fname, index=False)
 
     def dir(self):
diff --git a/environment.yml b/environment.yml
index 213a8a6..c659baa 100644
--- a/environment.yml
+++ b/environment.yml
@@ -10,7 +10,7 @@ dependencies:
   - h5py
   - pint
   - ruamel.yaml>=0.17.0
-  - pandas
+  - pandas>=1.4
   - cantera
   - setuptools
   - pytest